Method for operating an internal combustion engine

ABSTRACT

The invention concerns a method for operating an internal combustion engine ( 1, 18 ) having a plurality of combustion chambers ( 4 ), in the case of which the combustion chambers ( 4 ) are charged with fuel and air or with a fuel/air mixture. In order to prevent torque jumps from occurring when cylinders ( 3 ) of the internal combustion engine ( 1, 18 ) are shut down and when switching the operating mode of direct-injection internal combustion engines ( 18 ), it is proposed that the charging of the combustion chambers ( 4 ) with fuel and air or with a fuel/air mixture be controlled individually via open-loop or closed-loop control for each combustion chamber ( 4 ). In the case of a direct-injection internal combustion engine ( 18 ), a certain number of combustion chambers ( 4 ) can be operated with homogenous-charge operation, and the remaining combustion chambers ( 4 ) can be operated with stratified-charge operation in accordance with the level of torque required.

BACKGROUND OF THE INVENTION

The invention concerns a method for operating an internal combustionengine having a plurality of combustion chambers, in the case of whichthe combustion chambers are charged with fuel and air or with a fuel/airmixture.

The invention also concerns an internal combustion chamber having aplurality of combustion chambers that are capable of being charged withfuel and air or with a fuel/air mixture. Furthermore, the presentinvention concerns an electronic control unit for an internal combustionengine of this type.

The invention also concerns a memory element for an electronic controlunit of an internal combustion engine, in which said memory element acomputer program is stored that can be run on a computing element, inparticular on a microprocessor. The memory element is developed, inparticular, as a read-only memory, a random-access memory, or as a flashmemory. Finally, the invention concerns a computer program as well.

The invention concerns multiple-cylinder internal combustion engineswith fuel injection, i.e., conventional internal combustion engines withmanifold injection as well as direct-injection internal combustionengines having a more modern design. In the case of an internalcombustion engine with manifold injection, a fuel/air mixture isproduced in an intake manifold of the internal combustion engine andthen charged in the combustion chambers of the internal combustionengine. In the case of a direct-injection internal combustion engine,air alone enters the combustion chambers via the intake manifold.Depending on the operating mode of the internal combustion engine, fuelis injected directly into the combustion chambers of the internalcombustion engine at different points in time during a power cycle.

With regard for conventional internal combustion engines with manifoldinjection, it is known from the related art that a specified number ofcylinders can be shut down in certain operating states of the internalcombustion engine, e.g., in part-load operation or overrun, in order toreduce fuel consumption and exhaust-gas emissions. The cylinders areshut down by halting supply of fuel/air mixture to the cylinders to beshut down. This is accomplished by shutting down intake and/or exhaustvalves via which the fuel/air mixture enters the combustion chambersand/or exhaust gases leave the chambers after the fuel/air mixture iscombusted. The known method for shutting down cylinders has thedisadvantage that only a specified number of cylinders can be shut down.Moreover, sudden torque jumps that are clearly noticeable can occur incertain operating states when the cylinders are shut down or activated.

Direct-injection internal combustion engines can be operated indifferent operating modes. A distinction is made betweenstratified-charge operation, which is used with lower loads inparticular, and homogeneous operation, in which greater loads are placedon the internal combustion engine. Further operating modes are, e.g., anoperating mode for catalytic-converter heating, an operating mode fordesulfurization of a catalytic exhaust converter, or for NOx (oxides ofnitrogen) regeneration of a catalytic exhaust converter.

In stratified-charge operation, fuel is injected into a combustionchamber during a compression phase in such a fashion that, at the pointof ignition, a fuel cloud is located in the immediate vicinity of aspark plug. This injection can take place in different ways. Forexample, the injected fuel cloud can be located at the spark plug duringor immediately after injection, and is ignited by said spark plug. It isalso possible that the injected fuel cloud is first directed to thespark plug by means of a motion of the charge, and then ignited. In bothof these combustion processes, a stratified charge is present, notuniform fuel distribution.

The advantage of stratified-charge operation lies in the fact that itallows the internal combustion engine to respond to the lower loadsbeing placed on it using a very small amount of fuel. Larger loadscannot be responded to fully using stratified-charge operation.

In homogeneous operation, which is designed to respond to said largerloads, fuel is injected during an intake phase so it can be swirled and,therefore, distributed in the combustion chamber immediately. In thisregard, homogeneous operation is similar to the operating method ofconventional internal combustion engines with manifold injection.Homogeneous operation can also be used with lower loads, if necessary.

In stratified-charge operation, the throttle valve in the intakemanifold leading to the combustion chamber is opened wide, andcombustion is controlled via open-loop and/or closed-loop controlessentially only by means of the fuel mass to be sprayed. In homogeneousoperation, the throttle valve is opened and/or closed depending on thelevel of torque required, and the fuel mass to be sprayed is controlledvia open-loop and/or closed-loop control depending on the inducted airmass.

In both operating modes, i.e., in stratified-charge operation andhomogeneous operation, the fuel mass to be sprayed is also governed viaopen-loop and/or closed-loop control to a value that is optimal in termsof fuel economy, exhaust-gas reduction, and the like, depending on aplurality of further operating variables. Different types of open-loopand/or closed-loop control are used in the two operating modes.

During steady-state operation of a direct-injection internal combustionengine, operating states are possible in which the full level of torqueoutput by the internal combustion engine in the homogeneous operation isnot required, even though homogenous operation is requested based on asetpoint torque required by the internal combustion engine, i.e., due toa load being placed on the internal combustion engine. In these cases,due to the relatively rich fuel/air mixture in homogeneous operation(lambda=approx. 1), fuel consumption is relatively high, even though thefull level of torque generated in homogeneous operation is not required.

During dynamic operation of the internal combustion engine, i.e., whenchanging over between operating modes, rapid charge changes in thecombustion chambers can result in clearly noticeable, erratic changes inthe level of torque output by the internal combustion engine.

The present invention is based on the object of preventing torque jumpsduring operation of an internal combustion engine in a certain operatingstate, e.g., when shutting down cylinders or when changing over to adifferent operating mode.

To attain this object, the invention proposes, based on the method ofthe type mentioned initially, that the charging of the combustionchambers with fuel and air or with a fuel/air mixture be controlledindividually for each combustion chamber via open-loop or closed-loopcontrol.

SUMMARY OF THE INVENTION

With the method according to the invention, it is possible, for thefirst time, to charge the combustion chambers of individual cylinders ofan internal combustion engine in order to actively influence theoperating state of the internal combustion engine. The core of theinvention is not to compensate for charge differences individual to eachcylinder, but rather to intentionally charge the combustion chambers ofthe internal combustion engine with different charges. The charges candiffer according to the amount of fuel or air, or in terms of thecomposition of the fuel/air mixture with which the individual combustionchambers of the internal combustion chamber are charged. The charge ofthe combustion chambers can be controlled via open-loop or closed-loopcontrol, e.g., via electromechanically orelectrohydraulically-controlled intake or exhaust valves or via theinjection valves.

With the method according to the invention, torque jumps that occur,e.g., when individual cylinders of an internal combustion engine areshut down, or when changing over to a different operating mode of adirect-injection internal combustion engine, are prevented by means of asuitable open-loop or closed-loop control of the charge of theindividual cylinder chambers. Moreover, depending on the operating stateof the internal combustion engine, any number of cylinders can be shutdown. It would even be feasible to activate and/or shut down eachindividual cylinder of an internal combustion engine depending on theload being placed on said internal combustion engine.

In a steady-state operation of the internal combustion engine, some ofthe combustion chambers can be operated with full charge and the othercombustion chambers can be operated with just a partial charge. As aresult, a stratified charge, for example, can be realized in thecylinders with full charge and, in fact, at the operating points thatwould require that the entire internal combustion engine be operatedwith a homogeneous mixture (“throttled operation”) due to the torquerequired by the internal combustion engine when all combustion chambersare charged uniformly. A marked reduction in fuel consumption can beachieved as a result.

During dynamic operation of the internal combustion engine, i.e., whenchanging over between various operating modes, a sudden, undesiredchange in the torque output by the internal combustion engine can beprevented with the method according to the invention by means oftargeted open-loop or closed-loop control of the charging of thecombustion chambers. Feasible operating modes include, for instance,homogeneous operation, stratified-charge operation, lean-burnstratified-charge operation, operation for catalytic-converter heating,operation for desulfurization of the catalytic converter, or operationfor NOx (oxides of nitrogen) regeneration.

With the method according to the invention, torque jumps can thereforebe prevented when one or more cylinders are shut down, or when changingover to a different operating mode of the internal combustion engine.Additionally, the method according to the invention results in areduction in fuel consumption, particularly during steady-stateoperation.

According to an advantageous further development of the presentinvention, it is proposed that the charging of the combustion chamberswith fuel and air or with a fuel/air mixture be determined individuallyfor each combustion chamber. Based on the value determined for theactual charging of the combustion chambers, the charging of thecombustion chambers can be governed to a specifiable setpoint value.

According to a preferred exemplary embodiment of the present invention,it is proposed that the charging be measured by means of a charge sensorindividual to each combution chamber. A compression chamber pressuresensor, for example, can be used as charge sensor. The output signal ofthe charge sensor represents the actual charge in the combustionchamber.

According to an alternative exemplary embodiment of the presentinvention, it is proposed that the charging be modelled based on a levelof torque detected individually for each combustion chamber. The levelof torque that is detected can be either the actual torque or a setpointtorque. With reference to a torque model, the cylinder-specific chargeof the individual combustion chambers can be modelled based on theactual torque as well as the setpoint torque. In a reciprocalapplication, and calculated individually for each cylinder, the torquemodel can also be used to calculate the number of cylinders that must beoperated with a homogeneous mixture in order to obtain a requiredsetpoint torque. Stratified-charge operation continues in the rest ofthe cylinders, which provides good fuel economy.

According to another advantageous further development of the presentinvention, it is proposed that, to shut down cylinders, the charging ofthe combustion chambers of the cylinders to be shut down be reduced witha time delay between each one.

According to yet another advantageous further development of the presentinvention, it is proposed—for direct-injection internal combustionengines, in the case of which the combustion chambers are chargeddirectly with fuel and air—that, to change the operating mode of theinternal combustion engine, the charge of the combustion chambers beadapted to the operating mode to be switched to with a time delaybetween each one. For example, when changing over from stratified-chargeoperation to homogenous operation, all cylinders are not changed oversimultaneously. Instead, the individual cylinders are switched tohomogeneous operation in succession with a time delay between each one.Adaptation of the charge to a certain operating mode comprises, e.g.,the amount of fuel and air, the start of injection, and the compositionof the fuel/air mixture.

According to yet another advantageous further development of the presentinvention, it is proposed for direct-injection internal combustionengines that a certain number of combustion chambers be operated with acharge corresponding to homogeneous operation and the remainingcombustion chambers be operated with a charge corresponding tostratified-charge operation, in accordance with a setpoint torquerequired by the internal combustion engine. In this manner, the torqueoutput by the internal combustion engine can be adapted individually toa load being placed on the internal combustion engine. When a load beingplaced on an internal combustion engine that is greater than a level oftorque that can be output by the internal combustion engine instratified-charge operation, then it is no longer necessary—as it usedto be—to switch all cylinders in the internal combustion engine tohomogeneous operation. Instead, the fewest number of cylinders of theinternal combustion engine as possible are operated in homogeneousoperation that still allows the internal combustion engine to outputjust enough torque to correspond to the load being applied. Insteady-state operation of the internal combustion engine, this resultsin a considerable reduction in fuel consumption.

Of particular significance is the realization of the method according tothe invention in the form of a memory element that is provided for anelectronic control unit of an internal combustion engine. A computerprogram is stored in the memory element, which said computer program canbe run in a computing element, in particular in a microprocessor, andwhich is suitable for carrying out the method according to theinvention. In this case, the invention is therefore realized by means ofa program stored in the memory element, so that this memory elementequipped with the computer program represents the invention in the samefashion as the method that the computer program is suited to carry out.An electrical memory medium is particularly suited for use as the memoryelement, e.g., a read-only memory, a random-access memory, or a flashmemory.

The invention also concerns a computer program that is suitable forcarrying out the method according to the invention when it runs on acomputing element, in particular on a microprocessor. It is particularlypreferrable for the computer program to be stored on a memory elementfor an electronic control unit of an internal combustion engine. Thememory element is developed, in particular, as a read-only memory, as arandom-access memory, or as a flash memory.

As a further means of attaining the object of the invention, it isproposed—based on the electronic control unit for an internal combustionengine of the type named initially—that the electronic control unitcontrol—via open-loop or closed-loop control—the charging of thecombustion chambers with fuel and air or with a fuel/air mixtureindividually for each combustion chamber.

Finally, as a means of attaining the object of the present invention, itis proposed—based on the internal combustion engine of the type namedinitially—that the charging of the combustion chambers with fuel and airor with a fuel/air mixture be controllable—via open-loop or closed-loopcontrol—individually for each combustion chamber.

Further features, potential applications, and advantages of theinvention result from the subsequent description of exemplaryembodiments of the invention that are presented in the drawings. Alldescribed or depicted features form the object of the invention alone orin any combination, independent of their summarization in the claims ortheir back reference, and independent of their formulation and/ordepiction in the description and/or in the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of an internal combustion engine according tothe invention according to a first preferred exemplary embodiment;

FIG. 2 is a block diagram of an internal combustion engine according tothe invention according to a second preferred exemplary embodiment;

FIG. 3 is a flow chart of a method, according to the invention,according to a first preferred exemplary embodiment;

FIG. 4 is a flow chart of a method, according to the invention,according to a preferred exemplary embodiment;

FIG. 5 is a method, according to the invention, according to a thirdpreferred exemplary embodient; and

FIG. 6 is an operating program map based on FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 is an illustration of an internal combustion engine of a motorvehicle according to the invention, labelled in entirety with referencenumeral 1. In the case of the internal combustion engine 1, a piston 2is situated in a cylinder 3 in a manner that allows it to perform areciprocating motion. The cylinder 3 is equipped with a combustionchamber 4 that is bordered by the piston 2, an intake valve 5, and anexhaust valve 6, among other things. An intake manifold 7 is coupledwith the intake valve 5, and an exhaust manifold 8 is coupled with theexhaust valve 6. Instead of just one intake valve 5 and one exhaustvalve 6, a plurality of intake valves 5 and/or exhaust valves 6 can alsobe provided.

The internal combustion engine 1 comprises a plurality of such cylinders3, only one of which is shown in FIG. 1.

A fuel injector 9 projects into the intake manifold 7, via which fuelcan be injected into the intake manifold 7. The sprayed fuel combineswith air in the intake manifold 7 to form a fuel/air mixture thattravels through the intake valve 5 and into the combustion chamber 4. Aspark plug 10 projects into the combustion chamber 4 in the region ofthe intake valve 5 and the exhaust valve 6, with which the fuel/airmixture can be ignited in the combustion chamber 4.

A turnable throttle valve 11 is situated in the intake manifold 7, viawhich air can be supplied to the intake manifold 7. The amount ofsupplied air depends on the angular position of the throttle valve 11. Acatalytic converter 12 is located in the exhaust manifold 8, which saidcatalytic converter serves to clean exhaust gases produced by thecombustion of fuel.

The piston 2 is set into a reciprocating motion by the combustion offuel in the chamber 4, which said reciprocating motion is transferred toa not-shown crankshaft and exerts torque on said crankshaft.

An electronic control unit 13 is acted upon by input signals 14 thatrepresent operating variables of the internal combustion engine 1measured using sensors. For example, the electronic control unit 13 isinterconnected with an air-mass sensor, a lambda sensor, a speed sensor,and the like. The electronic control unit 13 generates output signals15, with which the behavior of the internal combustion engine 1 can beinfluenced via actuators and control elements. For example, theelectronic control unit 13 is interconnected with the fuel injector 9,the spark plug 10, the throttle valve 11, and actuators to actuate theintake and exhaust valves 5, 6 and the like, and it generates thesignals required to trigger them.

The electronic control unit 13 is provided, e.g., to control theoperating variables of the internal combustion engine 1 via open-loop orclosed-loop control. For example, the fuel mass sprayed into the intakemanifold 7 by the fuel injector 9 is controlled via open-loop and/orclosed-loop control by the electronic control unit 13 with regard forlow fuel consumption and/or low fuel emissions in particular. For thispurpose, the electronic control unit 13 is equipped with amicroprocessor 16 that runs a program that is suitable for carrying outthe stated open-loop and/or closed-loop control. The program is storedin a memory element 17, in particular in a flash memory, of theelectronic control unit 13.

In the case of an internal combustion engine 1 having a large number ofcylinders 3, in particular in the case of 6-cylinder or 12-cylinderinternal combustion engines, the method according to the invention(refer to FIG. 3) allows a variable number of cylinders 3 to be shutdown in certain operating states of the internal combustion engine 1,e.g., in part-load operation or in overrun.

The method according to the invention for shutting down cylinders 3starts in a function module 20. In a function module 21, the internalcombustion engine 1 is operated with all available cylinders 3. In aninquiry block 22, a load being placed on the internal combustion engine1 is compared with a level of torque being output by the internalcombustion engine 1. If the load being placed thereon is nearly equal tothe level of torque being output, the process returns to function module21, and the internal combustion engine 1 continues to operate with allavailable cylinders 3.

If the load being placed on the internal combustion engine 1 is lessthan the torque being output by the internal combustion engine 1,however, the process jumps to a function module 23, where the number ofcylinders 3 is determined that actually need to operate in order tooutput a level of torque corresponding to the load being applied. Thedifference between the total number of cylinders 3 and the number ofcylinders 3 required is the number of cylinders 3 that can be shut down.In a function module 24, one of the cylinders 3 to be shut down is shutdown.

To accomplish this, the capacity of the combustion chamber 4 assigned tothe cylinder 3 to be shut down is reduced to zero. This can take place,for example, by deactivating the appropriate intake valve 5, so that nofuel/air mixture can reach the combustion chamber 4. As an alternative,the injected fuel mass can be reduced to zero by means of suitablecontrol of the fuel injector 9.

A check is then carried out in an inquiry block 25 to determine if allcylinders 3 to be shut down have already been shut down. If additionalcylinders 3 remain to be shut down, the process jumps via a functionmodule 26 to function module 24, where the next cylinder 3 to be shutdown is shut down. In function module 26, the procedure is temporarilydelayed. As a result of this, the cylinders 3 to be shut down are shutdown with a time delay between each one. This prevents sudden torquejumps from occurring when the cylinders 3 are shut down.

If all cylinders 3 to be shut down are shut down, the internalcombustion engine 1 is operated in a function module 27 with a reducednumber of cylinders. In function module 28, the method according to theinvention is terminated. The activation of additional cylinders 3 cantake place in similar fashion.

The method in FIG. 3, which was explained with reference to the internalcombustion engine 1 with manifold injection in FIG. 1, can also be usedwith a direct-injection internal combustion engine 18, of course, asshown in FIG. 2. In the case of the internal combustion engine 18 inFIG. 2, the fuel injector 9 projects into the combustion chamber 4 inthe region of the intake valve 5 and the exhaust valve 6. Thedirect-injection internal combustion engine 18 can be operated in anumber of different operating modes. It is possible, for example, tooperate the internal combustion engine 18 in a homogeneous operation, astratified-charge operation, a homogeneous lean-burn operation, anoperation to heat the catalytic converter 12, an operation todesulfurize the catalytic converter 12, an operation for regeneration ofa NOx (oxides of nitrogen) storage catalyst, or the like.

In homogeneous operation, fuel is sprayed by the fuel injector 9directly into the combustion chamber 4 of the internal combustion engine18 during the intake phase. As a result, the fuel is still swirledextensively until ignition takes place, so that a substantiallyhomogeneous fuel/air mixture is produced in the combustion chamber 4.The level of torque to be generated is adjusted essentially by theelectronic control unit 13 via the position of the throttle valve 11. Inhomogeneous operation, the operating variables of the internalcombustion engine 18 are controlled via open-loop and/or closed-loopcontrol in such a fashion that lambda is equal to zero. Homogeneousoperation is used with wide-open throttle in particular.

Homogenous lean-burn operation is substantially similar to homogeneousoperation, but lambda is set to a value less than 1.

In stratified-charge operation, fuel is sprayed by the fuel injector 9directly into the combustion chamber 4 of the internal combustion engine18 during the compression phase. A homogeneous mixture is therefore notpresent in the combustion chamber 4 when ignition by the spark plug 10takes place; instead, a coating of fuel is present. Apart fromrequirements, e.g., exhaust-gas recirculation and/or tank ventilation,the throttle valve 11 can be opened completely, and the internalcombustion engine 18 can therefore be operated unthrottled. The leveltorque to be generated is adjusted largely via the injected fuel mass instratified-charge operation. With stratified-charge operation, theinternal combustion engine 18 can be operated at idle, in part-loadoperation or in overrun, in particular.

Alternation back and forth between the stated operating modes of theinternal combustion engine 18 can take place. Changeovers of this natureare carried out by the electronic control unit 13. To this end, afurther program is stored on the memory element 17 that can be run onthe microprocessor 16 and is suitable for performing the open-loop orclosed-loop control of the operating mode of the internal combustionengine 18.

A flow chart of a method according to the invention for changing theoperating mode of the internal combustion engine 18 (installedoperation) is shown in FIG. 4. The method begins in a function module30. In a function module 31, the internal combustion engine 18 isoperated in a first operating mode (stratified-charge operation). Sincestratified-charge operation, as described hereinabove, is only suitablefor low loads, a second operating mode (homogeneous operation) must beswitched to when greater loads are placed on the internal combustionengine 1. According to the invention, all cylinders 3 of the internalcombustion engine 18 are not changed over to homogeneous operationsimultaneously; this prevents sudden torque jumps from occurring whenalternating between operating modes.

In a function module 32, one of the cylinders 3 is changed over tohomogenous operation by charging it with a charge corresponding tohomogeneous operation. A check is then carried out in an inquiry block33 to determine if all cylinders 3 were changed over to homogeneousoperation. If additional cylinders 3 remain to be changed over, theprocess jumps via a function module 34 to function module 32, where thenext cylinder 3 is switched to homogeneous operation by filling thecombustion chamber 4 assigned to this cylinder 3 with a chargecorresponding to homogeneous operation. In function module 34, theprocedure of carrying out the method according to the invention istemporarily delayed, so that the individual cylinders 3 are switchedwith a time delay between each one. As a result of this, torque jumpsare prevented when switching between operating modes. A changeover fromhomogeneous operation to stratified-charge operation, or a changeoverbetween any other operating modes can take place according to the methoddescribed.

A flow chart of a further method according to the invention foroperating an internal combustion engine 18 in a steady-state operationis shown in FIG. 5. The method starts in a function module 50. In afunction module 51, the internal combustion engine 18 is operated in afirst operating mode (stratified-charge operation). In a function module52, a higher level of torque is required, since a higher load is beingplaced on the internal combustion engine 1. According to the invention,however, not all cylinders 3 of the internal combustion engine 18 arechanged over to homogeneous operation, just a number of cylinders 3required to output a level of torque that is greater than the load beingapplied. In a function module 53, the number of cylinders 3 isdetermined that must be operated in homogeneous operation so that theinternal combustion engine 18 can output the level of torque required.

In a function module 54, one of the cylinders 3 to be changed over isfirst switched to homogeneous operation by charging the combustionchamber 4 assigned to this cylinder 3 with a charge corresponding tohomogeneous operation. A check is then carried out in an inquiry block55 to determine if all cylinders 3 to be changed over to homogeneousoperation have already been changed over to homogeneous operation. Ifadditional cylinders 3 remain to be changed over to homogeneousoperation, the process jumps via a function module 56 back to functionmodule 54, where a further cylinder 3 is changed over to homogeneousoperation. In functional module 56, the procedure of carrying out themethod according to the invention is temporarily delayed, so that thecylinders 3 to be switched can be changed over to homogeneous operationwith a time delay between each one. As a result of this, torque jumpsare prevented when alternating between operating modes.

If all cylinders 3 to be switched were changed over to homogeneousoperation, the internal combustion engine 1 is operated for the timebeing in the “expanded operating mode” taking place at this time, inwhich some of the cylinders 3 of the internal combustion engine 1 areoperated in homogeneous operation and the remaining cylinders 3 areoperated in stratified-charge operation. An operating program map of thedirect-injection internal combustion engine 18 in FIG. 2 is shown inFIG. 6. The operating program map is plotted against speed n and torqueM. The expanded operating mode is labelled with reference numeral 40.Stratified-charge operation is labelled with reference numeral 41,homogeneous operation is labelled with reference numeral 42, andhomogeneous lean-burn operation is labelled with reference numeral 43.The expanded operating range 40 extends past stratified-charge operation41 into homogeneous lean-burn operation 43. The method according to theinvention is terminated in function module 58.

By means of the method according to the invention presented in FIG. 5,it can be ensured that the internal combustion engine 18 outputs a levelof torque corresponding to a higher load being applied, and that fuelcan be saved, since only as many cylinders as necessary are operated inhomogeneous operation, and as many cylinders 3 as possible are operatedin stratified-charge operation.

1. A method of operating an internal combustion engine having aplurality of combustion chambers, comprising the steps of charging thecombustion chambers with fuel and air or with a fuel/air mixture;determining an actual charging of the combustion chambers with fuel andair or with a fuel/air mixture individually for each combustion chamber;controlling the charging of the combustion chambers with fuel and air orwith a fuel/air mixture individually via a control selected from thegroup consisting of an open-loop control and a closed-loop control foreach combustion chamber; and measuring the actual charging of thecombustion chambers by means of a charge sensor individual to eachcombustion chamber.
 2. A method as defined in claim 1; and furthercomprising in order to shut down cylinders, reducing the charging of thecombustion chambers of the cylinders to be shut down with a time delaybetween each one.
 3. A method as defined in claim 1; and furthercomprising, in order to switch an operating mode of the internalcombustion engine, adapting the charging of the combustion chambers tothe operating mode to be switched to with a time delay between each one.4. A method as defined in claim 1; and further comprising charging thecombustion chambers with fuel and air directly; operating a certainnumber of combustion chambers with a homogenous-charged operation; andoperating remaining combustion chambers with a stratified-chargeoperation, in accordance with a level torque required by the internalcombustion engine.
 5. A computer program storable on a readable storagemedium and programmed to carry out a method of operating an internalcombustion engine having a plurality of combustion chambers, comprisingthe steps of charging combustion chambers with fuel and air or with afuel/air mixture, determining an actual charging of the combustionchambers with fuel and air or with a fuel/air mixture individually foreach combustion chamber, controlling the charging of the combustionchambers with fuel and air or with a fuel/air mixture individually via acontrol selected from the group consisting of an open-loop control and aclosed-loop control for each combustion chamber, and measuring theactual charging of the combustion chambers by means of a charge sensorindividual to each combustion chamber.
 6. An electrical memory mediumformed as a readable storage medium for a control device selected fromthe group consisting of an open-loop control device and a closed-loopcontrol device of an internal combustion engine, the electrical memorymedium having a computer program storable on the electrical memorymedium and programmed to carry out a method of operating an internalcombustion engine having a plurality of combustion chambers, comprisingthe steps of charging the combustion chambers with fuel and air or witha fuel/air mixture, determining an actual charging of the combustionchambers with fuel and air or with a fuel/air mixture individually foreach combustion chamber, controlling the charging of the combustionchambers with fuel and air or with a fuel/air mixture individually via acontrol selected from the group consisting of an open-loop control and aclosed-loop control for each combustion chamber, and measuring theactual charging of the combustion chambers by means of a charge sensorindividual to each combustion chamber.
 7. An electrical memory medium asdefined in claim 6, wherein the memory medium is developed as a mediumselected from the group consisting of a read-only memory, arandom-access memory, and a flash memory.
 8. A control device selectedfrom the group consisting of an open-loop control device and aclosed-loop control device for an internal combustion engine providedwith means for charging combustion chamber with fuel and air or with afuel/air mixture, the control device having means for controlling thecharging of the combustion chambers with fuel and air or with a fuel/airmixture individually via a control selected from the group consisting ofan open-loop control and a closed-loop control for each combustionchamber; and means for measuring the actual charging of the combustionchambers by means of a charge sensor individual to each combustionchamber.
 9. An internal combustion engine for a motor vehicle,comprising a control device selected from the group consisting of anopen-loop control device and a closed-loop control device and havingmeans for charging combustion chambers with fuel and air or with afuel/air mixture; means for determining an actual charging of thecombustion chambers with fuel and air or with a fuel/air mixtureindividually for each combustion chamber; means for controlling thecharging of the combustion chambers with fuel and air or with a fuel/airmixture individually via a control selected from the group consisting ofan open-loop control and a closed-loop control for each combustionchamber; and means for measuring the actual charging of the combustionchambers by means of a charge sensor individual to each combustionchamber.
 10. A method of operating an internal combustion engine havinga plurality of combustion chambers, comprising the steps of charging thecombustion chambers with fuel and air or with a fuel/air mixture;determining an actual charging of the combustion chambers with fuel andair or with a fuel/air mixture for each combustion chamber individually;controlling the charging of the combustion chambers with fuel and air orwith a fuel/air mixture individually via a closed-loop control for eachcombustion chamber, and in order to shut down the cylinders, reducingthe charging of the combustion chambers in the cylinders to be shut downwith a time delay between each one.
 11. A method as defined in claim 10;and further comprising measuring the charging by means of a chargesensor individual to each combustion chamber.
 12. A method as defined inclaim 11; and further comprising charging the combustion chambers withfuel and air directly; and in order to switch the operating mode of theinternal combustion engine, adapting the charge of the combustionchambers to the operating mode to be switched too with a time delaybetween each one.
 13. A method as defined in claim 10; and furthercomprising modeling a charge based on a level torque detectedindividually for each combustion chamber.
 14. A method as defined inclaim 10; and further comprising charging the combustion chambers withfuel and air directly; and cooperating a certain number of combustionchambers with a homogenous-charge operation, and operating a remainingcombustion chambers with a stratified-charge operation in accordancewith a level torque required by the internal combustion engine.
 15. Acomputer program storable on a readable storage medium and programmed tocarry out a method of operating an internal combustion engine having aplurality of combustion chambers, comprising the steps of charging thecombustion chamber switch fuel and air or with a fuel/air mixture,determining an actual charging of the combustion chambers with fuel andair or with a fuel/air mixture for each combustion chamber individually,controlling the charging of the combustion chambers with fuel and air orwith a fuel/air mixture individually via a closed-loop control for eachcombustion chamber, and in order to shut down the cylinders, reducingthe charging of the combustion chambers in the cylinders to be shut downwith a time delay between each one.
 16. An electrical memory mediumformed as a readable storage medium for a control device selected fromthe group consisting of an open-loop control device and a closed-loopcontrol device of an internal combustion engine, the electrical memorymedium having a computer program storable on the electrical memorymedium and programmed to carry out a method of operating an internalcombustion engine having a plurality of combustion chambers, comprisingthe steps of charging the combustion chambers with fuel and air or witha fuel/air mixture, determining an actual charging of the combustionchambers with fuel and air or with a fuel/air mixture for eachcombustion chamber individually, controlling the charging of thecombustion chambers with fuel and air or with a fuel/air mixtureindividually via a closed-loop control for each combustion chamber, andin order to shut down the cylinders, reducing the charging of thecombustion chambers in the cylinders to be shut down with a time delaybetween each one.
 17. An electrical memory medium as defined in claim16, wherein the memory medium is developed as a medium selected from thegroup consisting of a read-only memory, a random-access memory, and aflash memory.
 18. A control device selected from the group consisting oran open-loop control device and a closed-loop control device for aninternal combustion engine provided with means for charging combustionchambers with fuel and air or with a fuel/air mixture, the controldevice having means for controlling the charging of the combustionchambers with fuel and air or with a fuel/air mixture individually via aclosed-loop control for each combustion chamber, and in order to shutdown the cylinders, means for reducing the charging of the combustionchambers in the cylinders to be shut down with a time delay between eachone.
 19. An internal combustion engine for a motor vehicle provided withmeans for charging combustion chambers with fuel and air or with afuel/air mixture, comprising a control device selected from the groupconsisting of an open-loop control device and a closed-loop controldevice and having means for determining an actual charging of thecombustion chambers with fuel and air or with a fuel/air mixture foreach combustion chamber individually, means for controlling the chargingof the combustion chambers with fuel and air or with a fuel/air mixtureindividually via a closed-loop control for each combustion chamber, andin order to shut down the cylinders, means for reducing the charging ofthe combustion chambers in the cylinders to be shut down with a timedelay between each one.
 20. A method of operating a direct-injectioninternal combustion engine having a plurality of combustion chambers,comprising the steps of charging the combustion chambers with fuel andair or with a fuel/air mixture; determining an actual charging of thecombustion chambers with fuel and air or with a fuel/air mixtureindividually for each combustion chamber; controlling the charging ofthe combustion chambers with fuel and air or with a fuel/air mixtureindividually via a closed-loop control for each combustion chamber; andin order to switch the operating mode of the internal combustion engine,adapting the charging of the combustion chambers to the operating modeto be switched to with a time delay between each combustion chamber. 21.A method as defined in claim 20; and further comprising operating acertain number of combustion chambers with homogenous-charge operation;and operating a remaining combustion chambers with a stratified-chargeoperation in accordance with a torque required of the internalcombustion engine.
 22. A method as defined in claim 20; and furthercomprising, in order to shut down cylinders, reducing a charge of thecombustion chambers of the cylinders to be shut down with a time delaybetween each one.
 23. A method as defined in claim 20; and furthercomprising measuring the charge by means of a charge sensor individualto each combustion chamber.